Recently, an ECU (Electronic Control Unit) is installed in each vehicle so as to achieve the function of controlling its engine under the ECU. The ECU is one type of computer that achieves predetermined functions according to computer programs. Normally, already-used vehicles have been updated in computer programs for each ECU at inspections or periodical inspections of vehicles in ordinal automobile repair shops.
Conventionally, a workman handling updating of computer programs for each ECU connects a maintenance-dedicated diagnostic terminal to a diagnostic port called a vehicle OBD (On-Board Diagnostics) port so as to install updating programs or change data settings with the diagnostic terminal. For example, Non-Patent Literatures 1 and 2 disclose securities for vehicles.